HDD in Denmark Horizontal Directional

Contractor Soren Knudsen A/S has completed an HDD boring project in an environmental sensitive area in Denmark. The project involved pulling back 110-mm PE pipe approximately 342 m.  

The electrical supply cable to the little island of Hindo in Stadil inlet was out of order and a new cable was required. Hindo, the low water area around the island, as well as  Svellebusk have been declared as “environmentally protected areas” by the Danish government — which means open-trenching is no longer permitted in those areas.

Soren Knudsen A/S was asked to complete the project using horizontal directional drilling (HDD) — boring between the main land and the island. The boring would take place 300 m under water, plus some extra meters on each side of the water; this involved approximately 20 m on the main land for going under some dikes and also approximately 20 m on the island for boring beneath a meadow.

The Bore

The boring was done in one working day, starting early in the morning and finishing at 7:30 p.m., which including three magazine changes each way. The biggest challenge was to get the 110-mm PE pipe to the target pit due to the very soft soil on the island of Hindo.

Soren Kundsen A/S decided to use its Grundodrill 8S, manufactured by Tracto-Technik, for the job. The contractor has used this machine since 2003 and has logged more than 5,500 hours with it since that time.

Soren Knudsen A/S was the first company outside Germany to invest in Grundodrill bore rigs in northern Europe. They got their first machine in 1994 — a first Grundodrill with  6.5 tons of thrust and pullback. They were also the first to get a Grundohit in 1996 — a unique machine in the industry that was designed for surface launch and pit launch applications. Several years later, Søren Knudsen switched to the more modern and efficient Grundodrill 8S version.

On the Hindo island project, Soren Kundsen A/S also used a DCI Eclipse detection system from a boat in the inlet at a maximum depth of 8 m. The drilling fluid was bentonite from MI, with a mix of 25 kg of Max Bore and 0.25 kg of PAC per m3 of fluid. Ultimately the project was completed to the satisfaction of all parties involved, with significant credit being given to Bent and Lasse from Soren Knudsen for a job well done.

So after this job was complete, Soren Knudsen A/S was ready for its next special job, which was a 400-m HDD project involving 110-mm PE pipe, also using its Grundodrill 8S drill.

Gunnar Guldbrand has been a sales partner with Tracto-Technik, Lennestadt, Germany, for more than 30 years.